Change selected GPIO for one-wire DT overlay package

[greenbreakfast]

Context

Specify which branch of this repo or firmware version you're referring to

openwrt-22.03 branch onion-dt-overlay-w1-gpio package

Motivation

Why are we doing this? What use cases does it support? What problems does it solve? What is the expected outcome?

Support for one-wire devices was added in #53 with GPIO19 arbitrarily chosen as the one-wire bus master pin

If your feature request is related to a problem, provide a clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

Changing the one-wire bus master pin to a different GPIO would free up GPIO19 (and hardware PWM channel 1).

The new GPIO for the one-wire bus master should ideally be:

• a GPIO that is not multiplexed with other functionality
• pinned out both the Omega2 and Omega2S variants

Good candidates are GPIOs 0, 1, 2, or 3

Description

A clear and concise description of what you want to happen. It should be reasonably clear how the improvement would be implemented.

Update the onion-dt-overlay-w1-gpio package to use GPIO2

GPIO2 was selected from the candidate list by collaborating with @DocHardinger in issue #53

What does the output of this improvement look like?

A new version of the onion-dt-overlay-w1-gpio package released, documentation updated

Alternatives Considered

A clear and concise description of any alternative solutions or features you've considered.

• Keep using GPIO19 - not ideal because it takes up hw PWM channel1
• GPIO11 - avoid since the bootloader will always program it to output high (https://docs.onion.io/omega2-docs/using-gpios.html#reset-led-pins)
• GPIO41 - avoid since not pinned out on the Omega2/2+

Additional Resources

Add any other context or screenshots about the feature request here. Include links to any relevant source code repos

See issue #53 for original implementation of one wire dt overlay package

Reference to existing IPK package file?

Has this been done for other OpenWRT hardware?

N/A

[jempatel]

@greenbreakfast So we are going to use GPIO2 for one-wire now instead of GPIO19.

Pls correct me If I am wrong.

[greenbreakfast]

@jempatel yep, let's use GPIO2 for one-wire

Sorry if that was unclear in the issue. How can I adjust it to make that more clear?

[jempatel]

@greenbreakfast, It was clear from your message, I dropped a message just to double-confirm before pushing changes because in old firmware it was already using GPIO19

[greenbreakfast]

Tested on my end and works fine. Will go ahead and close this issue.

@amsiotdeveloper can you please make a new ticket to update the one wire documentation? The main update is that we now use GPIO2 as the one-wire master pin.

Along with that, here are some additional edits we should make:

• Enable One-Wire Device Support section: need to add a step before step 1 to do opkg update
• Find Connected One-Wire Devices section, Step 4: need to add space in command after cat

[amsiotdeveloper]

@greenbreakfast ticket has been created to update 1-wire article and it has been assigned to Muze

https://github.com/OnionIoT/documentation/issues/36

[greenbreakfast]

Thanks @amsiotdeveloper I'm good to close this ticket since the software part is complete